How Bad We Need Each Other
by Chalkolatedragun
Summary: In which Marshall's charms don't get him on good terms with Fionna again, and she hears a lullaby with a nonexistent bass. "I can't cross running water, love."


**Darn it, I've done it again. I need to stop obsessing over these two… oh well, I blame Bad Little Boy.**

**Disclaimer: I don't own Adventure Time.**

It looked like the duo, made up of human and vampire, had reached a problem.

The problem wasn't nearly as bad as it could have been. It was actually a small, friendly creek that gurgled happily. But it was still a problem.

"I can't cross running water," said Marshall, watching Fionna jump across the creek.

Fionna laughed. "Sure you can, dude! You're just messing with me." Marshall imitated her laugh, making it high and annoying.

"No, I can't, I'm not messing," he snapped. Fionna rolled her eyes.

"Just walk!" she chided. Marshall pouted, his fangs poking over his lip just slightly.

"But floating is so much better," he complained, "And I like these shoes!" Yet, he still drifted down, his feet sinking slightly into the soft mud. Fionna waded over and stood in front of him.

She grabbed his wrists and pulled backwards. Marshall hissed, his eyes turning into 'demon eyes' and narrowing into slits. He sliced at her with his claws and flung himself backwards, speeding through the sun into the nearby shadow of a tree.

"What the heck, man?!" Fionna demanded. Marshall sighed as he lighted himself down on a tree branch.

"I can't cross running water, love" he said, leaning his head on his hand. Deciding to let the little nickname go, Fionna walked over to the tree. Marshall looked down at her from between his knees.

"Why not?!"

He sighed, and fell backwards casually, hanging off the branch by his knees. Fionna walked to the other side of him to get a better view of his face. He had his arms crossed, his hair hanging down, and his shirt slipping down a bit. "Demon's sixth law, love."

Fionna smacked the top –bottom? I'm not even sure- of his head. "I didn't give you permission to call me love!" she snapped, "You creeper!"

Marshall smirked. He poked her stomach and winked, snapping his jaws together. Fionna did the obvious choice; she jumped back and wrapped her arms around her tummy defensively.

"Oh, cool, it, _love_," he mocked, flipping down and stretching out next to her, floating lazily. "It's just a term of endearment, from a Pre-Mushroom War country called England. It's just sort of a pet name, like how Cake calls you 'honey' and 'baby'."

"Cake's my sister, ya freak." Marshall sighed.

"Oh, calm down, Fi. There!" he said suddenly, his eyes brightening. "That's how I meant it! Like a nickname! Like how I call you Fi!"

"I hate being called Fi."

"No you don't."

"That doesn't change the fact we need to get you over the river," Fionna snapped. Marshall smiled dryly.

"I liked you more when you were twelve. You weren't so pissy and hormonal and stuff."

*_Smack!*_

_*Bitch Slap!*_

"Ouch, I'm sorry, I'm sorry!" He sighed. "I probably deserved that, didn't I?"

"Heck ya you did. Listen to me, I need to freaking cross this river, so you can have fun trying to cross it yourself!" Fionna growled, stomping over to the river. Marshall floated gloomily and, with a lot of concentration, levitated his umbrella to him.

"You're such a wonderful friend," he said, watching her cross the river.

"Not gonna look back," Fionna muttered to herself. "He's tugging your heart guts. He's being the usual douche. Don't look back."

But she did, and he looked pretty damn guilty. "No, Fionna," she scolded herself. "He's done this before. He's been his douche-y, jackbutt self, and then you fall under his charms and forgive him. Not today."'

"It's the tenth today, isn't it?!" Fionna made a rude gesture at him.

"Who taught you that?!"

"You did!"

~0~0~0~

Fionna was crying, she was so happy. For the past few months, Cake had been in trouble. Being pregnant was pretty hard on her. But now there were healthy cute little baby Mochro Cake things. Cake was snuggling her babies.

There was a soft knock on the door. "Can I come in?"

"No."

"Fionna!"

"What?"

Cake sighed. "Come on in, Marshall," she said, giving Fionna a hard look. While Cake was pregnant, Marshall had been uncharacteristically… nice. He would act as a gentleman, opening doors and trying to rush around to make Cake as comfortable as possible. He was also always trying to help, trying to find age-old medicines and cures to help with anything, from back pains to, well, whatever.

Marshall slowly came in, his guitar slung around his back. "Are these the kits?" he asked. He looked like crap, all splattered with mud and stuff.

"Mhmm!" said Cake, introducing each one. Marshall was standing by the front of the bed, seeming like he was smitten with the kids.

"Can I… hold one?" Cake reluctantly let him carefully coax one baby over to him.

"_Soft kitty, warm kitty, little ball of fur,_

_Happy kitty, sleepy kitty, purr, purr, purr_," he sang softly, carefully holding out a finger. The rest of the babies wandered over to him. He smiled. "Hey, at least someone likes me," he said.

Doctor Ice Cream came in and shooed Fionna and Marshall out. "You can wait in the lobby, sleep there, if you want to," he said sternly, "but Cake has been through a lot and all she needs is some time to rest with her children.

Not many people were in the lobby. A restless kid played with some toys, while a bored teenage nurse kept a close eye on them.

Marshall was picking the strings on his guitar, trying to match his voice to the chord. Fionna was silent, picking at a weird stain on her skirt that looked suspiciously like tomato sauce.

"I'm sorry."

"You're not welcome." Marshall was quiet for a few beats while the nurse led the kid away.

"Look, I know I was being a douche, alright?"

"Well, then you certainly don't seem to mind it," snarled Fionna. Marshall rubbed his forehead. She could feel the air charged with something.

Guilt, maybe?

"So, what happened to you?" she asked, trying to change the subject. He laughed.

"I tried to cross the river the hard way. That didn't work, so I ended up having to go downstream to try and find where it ended so I could cross."

"Did it work?" He shrugged.

"More or less," he admitted.

Silence.

"Marshall?"

"Yeah, love?" He winced. "Sorry, old habits die hard, I guess. Yeah, Fi?-Onna?" This made Fionna laugh a little bit.

"… You can still call me Fi."

"Yes!" he said triumphantly, "Some old habits do not have to die hard!"

"But seriously, Marsh? Can you sing a lullaby?"

"Singing ain't really my thing. I'm more of a rapping typa dude."

"I'm tired. I want a lullaby, and you have a soothing voice."

"Did you just… complement me?"

"I'm stating the facts." Marshall smiled, and he began playing a tune. He began humming along first.

"_Life is too far to walk alone,_

_You can't do it on your own,_

_It's like bare hands digging through stone,_

_And if things go down much steeper hills,_

_Even money won't pay these bills,_

_But time will show you know,_

_People gonna be okay,_

_Storms never come to stay,_

_They just show us _

_How bad we need each other,_

_How bad we need each other,_

_And the trials of today,_

_They are signs along the way,_

_To remind us_

_How bad we need each other_

_How bad we need each other," _He sang, his voice soft and sweet, the tune coming out of his guitar mellow and soothing.

"You'd better not be trying to put ideas in my head while I sleep," Fionna muttered. Marshall chuckled.

"Sleep tight, bunny."

~0^0~

"So? What do you think?" Marceline asked. She and Ice King had decided to try and write a fanfiction together.

"Oh, yeah, it's great and all," said Ice King airily, "but it needs more, you know, action! Pa-pow! And hot older men!" he chided. Marceline's face fell.

"This-isn't-supposed-to-be-an-action-it's-supposed-to-be-" Marceline growled in irritation.

Ice King didn't want to lose his 'writing buddy'. He needed to think fast. Telling the princesses Marceline was working on his stories was the only thing that kept them even semi-quiet when he read to them. "What about that song? Can you sing some more of it?"

"Oh, uh, sure," said Marceline, adjusting her bass. "It's supposed to be on an acoustic, but I can try on bass. It'll be a little messed up," she said, and cleared her throat. She began with humming, like her 'fanfiction counterpart'.

"_And I can get so high,_

_On myself sometimes,_

_I keep on drifting a million miles_

_From this planet,_

_But what a shame it would be,_

_To look back on our lives,_

_And realize that I've taken you and you_

_For granted,_

_People gonna be okay,_

_Storms never come to stay,_

_They just show us how bad we need each other,_

_How bad we need each other…"_

_~0^0~_

Far away, in a land of mystic and magic, Fionna the Human fell asleep to Marshall's guitar, with the soft hum of a bass and female vocals in her ears.

~0^0~

And not so far away, Finn the Human was lulled to sleep by a song, played with an acoustic and bass, a duet with two unknowing participants.

**Aaaand done. Has anyone seen Bad Little Boy? It was great, believe me, but it just… wasn't what I expected. Marshall is a douche. He's a cute, endearing douche, but still a douche.**

**Plus, I love how he raps mostly instead of singing. Childish Vampino, everyone :D**

**This is supposed to take place when Cake gives birth to her and Mochro's babies, so before Bad Little Boy, I guess.**

**Song is How Bad We Need Each Other by Mark Scibilia. You should go and listen to it, it's a really nice song. And pay attention to what Marshall and Marceline are singing, because I didn't use the really rock-y type part. **

**So, the theory about demons not be able to cross the river: it's common, as far as my knowledge goes, so why not use it? Anyway, I guess some deep-rooted instict would activate, so that the demon would flip out and use everything in it's power to not cross. Hence the appearence of Marshall's demon eyes. I don't really know what would happen if they did cross it... maybe an interdimensional portal to a place worse than the Nitosphere? Hmm, soudns interesting.**

**Did you see the penguins?**

**Maybe if you peeps review about it, I'll post about Marshall trying to cross the river?**

**Oh, and look! It has more people than just the genderswap! Yay! Now, Imma go watch Hetalia...**

**Peace out,**

**Chalkolatedragun**


End file.
